/**
 * transformers.js (ONNX, dual-environment) Caption (image-to-text) specialist adapter battery.
 *
 * @module @nhtio/adk/batteries/specialists/caption/transformers_js/adapter
 *
 * @remarks
 * Image-captioning battery backed by transformers.js's `image-to-text` pipeline (the documented
 * reference model is `Xenova/vit-gpt2-image-captioning`). **Environment-neutral** — runs in Node (via
 * `onnxruntime-node`) and the browser (via `onnxruntime-web` / WebGPU), auto-selected by the package;
 * there is no WebGPU requirement.
 *
 * Same shape as the transformers.js Embeddings battery: eager constructor validation, a required
 * `model` (no default), a lazily-imported/single-flight peer, `preload()` / `reset()` / `dispose()`,
 * and the shared lifecycle hooks.
 *
 * **Image input:** {@link @nhtio/adk/batteries/specialists/_shared!toBytes} normalizes the accepted
 * {@link @nhtio/adk/batteries/specialists/_shared!SpecialistImageInput} forms (bytes / bytes+mime /
 * media-like) to plain bytes + an optional MIME type. Those bytes become a plain `Blob` — the
 * `image-to-text` pipeline's `ImageInput` union directly accepts `Blob` (verified against the
 * installed `@huggingface/transformers` 4.2.0 type declarations, alongside `string | RawImage | URL |
 * HTMLCanvasElement | OffscreenCanvas`), so building a `Blob` needs no peer import at all — `Blob` is a
 * cross-env global (Node 18+ and every browser). This keeps the adapter's hot path peer-free until the
 * pipeline itself is resolved, and means fake-pipeline unit tests never load `@huggingface/transformers`.
 *
 * `@huggingface/transformers` is an optional peer dependency, imported lazily (only inside
 * {@link makeDefaultCreatePipeline}, i.e. only when no `pipeline`/`createPipeline` override is supplied).
 */
import type { SpecialistImageInput } from "../../_shared/index";
import type { DescribeOptions, DescribeResult } from "./types";
/**
 * Caption (image-to-text) adapter for transformers.js's `image-to-text` pipeline.
 *
 * @remarks
 * Reusable: construct once, call {@link TransformersJsCaptionAdapter.describe} as many times as
 * needed. The pipeline is resolved lazily on first use (or via {@link preload}) and cached with
 * single-flight semantics so concurrent calls share one load.
 */
export declare class TransformersJsCaptionAdapter {
    #private;
    /**
     * Whether this battery is available. transformers.js is environment-neutral (Node + browser), so
     * this is `true` whenever the runtime can import the peer — there is no WebGPU requirement.
     */
    static isAvailable(): boolean;
    /**
     * @param options - Constructor options. Validated eagerly.
     * @throws {@link @nhtio/adk/batteries!E_INVALID_TRANSFORMERS_JS_CAPTION_OPTIONS} when invalid.
     */
    constructor(options: unknown);
    /** Instance availability probe (honours an injected `isAvailable`). */
    isAvailable(): boolean;
    /** Eagerly loads (and caches) the pipeline so the first `describe` call is fast. Idempotent. */
    preload(): Promise<void>;
    /** Drops the cached pipeline and in-flight load so the next call reloads. */
    reset(): void;
    /**
     * Release the loaded model's ONNX sessions + GPU/wasm buffers, then drop the cached pipeline.
     *
     * @remarks
     * `reset()` only nulls the JS reference; the native ONNX Runtime sessions and WebGPU/wasm device memory
     * stay alive until GC. `ImageToTextPipeline` extends `Pipeline`, which exposes `dispose()` — this
     * awaits it so the memory is reclaimed between loads, swallows a disposal error (teardown must not
     * throw), and finishes with `reset()`. Idempotent.
     */
    dispose(): Promise<void>;
    /**
     * Generates a caption for an image.
     *
     * @param input - The image in any {@link @nhtio/adk/batteries/specialists/_shared!SpecialistImageInput}
     *   form (bytes / bytes+mime / media-like).
     * @param opts - Per-call options (`maxNewTokens`, forwarded as `max_new_tokens`; omitted when unset).
     * @returns The normalized `{ text }` caption result.
     * @throws {@link @nhtio/adk/batteries!E_TRANSFORMERS_JS_CAPTION_ENGINE_ERROR} when the call fails or
     *   the pipeline returns no usable caption text (an empty/missing caption is treated as an engine
     *   failure, not a valid empty result — a captioner that produces nothing didn't do its job).
     */
    describe(input: SpecialistImageInput, opts?: DescribeOptions): Promise<DescribeResult>;
}